The present invention relates to applying tamper evident seals to relatively large diameter lidded circular containers. Typical examples are those containers used for popcorn, pretzels, or potato chips. In general, the seal for such containers takes the form of an adhesive tape covering the seam between the lid and the body of the container.
Particular problems arise when sealing such containers. One problem arises from the typical rolled lip construction of the lid, and the lipped or ridged shape of the upper portions of the cylindrical container which receive the lid. Because of these typical structures, the containers cannot always be handled as perfect cylinders.
Some previous sealing devices have tended to use a turntable type arrangement in which the cylinder to be sealed, travels in a circular path during which a strip of sealant material such as tape is applied to it. Although useful in certain circumstances, the turntables tend to occupy significant space and offer very little flexibility in terms of different sizes of containers. Such containers, however, vary widely in their dimensions--height and diameter--and these and other devices are often limited to handling only a single size of container.
Other devices are appropriate for sealing one container at a time, but require constant manual attention to remove a sealed container and replace it with an unsealed container to be sealed.
In other arrangements, the containers to be sealed must be raised or lowered during the sealing and lidding process, a procedure which greatly complicates the mechanical design of the resulting device.
In yet other arrangements, the adhesive tape sealing the container is moved in an orbital fashion around a stationary container. This likewise takes up a great deal of space and complicates the necessary arrangements.
Such prior devices have also lacked simple and effective indexing elements; i.e. elements that present the containers for sealing at regular intervals even when they arrive at irregular intervals.
Therefore, the need exists for a fairly simple and straightforward method and associated apparatus for applying a sealing tape to lidded containers. In particular, the need exists for a method and apparatus which can appropriately index and then seal containers of different diameters and different heights, but without the need for overly complex techniques.